<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
</head>
<body>
    <script src="https://dl.dropboxusercontent.com/s/r55397ld512etib/EncoderDecoderTogether.min.js?dl=0" nomodule="" type="text/javascript"></script>
    <script src="https://cdn.jsdelivr.net/npm/promise-polyfill@8/dist/polyfill.min.js"></script>
    <script src="deps/jsSHA/dist/sha512.js"></script>
    <script type="text/javascript">

        function decodeBase64(base64) {
            const binStr = window.atob(base64);
            const len = binStr.length;
            const bytes = new Uint8Array(len);
            for (let i = 0; i < len; i++) {
                bytes[i] = binStr.charCodeAt(i);
            }
            return bytes;
        }

        function encodeBase64(bytes) {
            let binStr = "";
            for (let i = 0; i < bytes.length; i++) {
                binStr += String.fromCharCode(bytes[i]);
            }
            return window.btoa(binStr);
        }

        function subtleCryptoResult(promiseOrOp, method) {
            if (promiseOrOp instanceof Promise) {
                return promiseOrOp;
            } else {
                return new Promise(function(resolve, reject) {
                    promiseOrOp.oncomplete = function(e) {resolve(e.target.result);}
                    promiseOrOp.onerror = function(e) {
                        reject(new Error("Crypto error on " + method));
                    }
                });
            }
        }

        const subtleCrypto = (window.crypto || window.msCrypto).subtle;

        function computeFallback(key, data, hash) {
            const shaObj = new jsSHA(hash, "UINT8ARRAY", {
                "hmacKey": {
                    "value": key,
                    "format": "UINT8ARRAY"
                }
            });
            shaObj.update(data);
            return Promise.resolve(shaObj.getHash("UINT8ARRAY"));
        }

        function compute(key, data, hash) {
            const opts = {
                name: 'HMAC',
                hash: {name: hash},
            };
            return subtleCryptoResult(subtleCrypto.importKey(
                'raw',
                key,
                opts,
                false,
                ['sign']
            ), "importKey").then(function (hmacKey) {
                console.log("hmacKey", hmacKey);
                return subtleCryptoResult(subtleCrypto.sign(
                    opts,
                    hmacKey,
                    data
                ), "sign");
            }).then(function(buffer) {
                return new Uint8Array(buffer);
            });
        }

        const te = new TextEncoder();
        computeFallback(
            new Uint8Array(te.encode("I am a key!!")),
            new Uint8Array(te.encode("I am some data!!")),
            "SHA-512"
        ).then(function(mac) {
            // should be 9bpJS7myNR/ttCfts+woXJSapVb19qqFRntGh17rHydOBB8+pplZFG8Cc4Qkxxznri4nWyzhFWcWnenY9vd5rA==
            alert(encodeBase64(mac));
        })
    </script>
</body>
</html>
 
